Oregon
State
University
.
rop Science Report
RESEARCH/EXTENSION
ERGOT IN CEREAL GRAINS CAUSE, HAZARDS, AND CONTROL
Russ Karow
1
Introduction
Reports of ergot in harvested grain have been received from all parts
The purpose of this report is to provide informaof Oregon this year.
tion on the disease, on the potential hazards of feeding ergoty grain,
and on control measures.
What is ergot?
Ergot is a fungal organism (Claviceps purpurea) which replaces one or
more of the kernels in a mature grain head with a hard, dark colored,
This fungal mass may have the shape
horn-like mass called a sclerotia.
of the kernel that it has replaced or it may be two to four times the
Intact or broken sclerotia are easily seen
length of a normal kernel.
Ergot most easily attacks rye (a cross-pollinated
in harvested grain.
grain), but it also can infect barley, wheat, oats, and other native
and cultivated grasses including weeds such as quackgrass.
How does ergot grow and spread?
The
The fungus lives through the winter in the horn-like sclerotia.
sclerotia must be exposed to cold (36-37° F) for several weeks in order
In the spring, parts of the fungus within the sclerotia
to germinate.
begin to grow and after breaking the
sclerotia coating form one to several
mushroom-like growths called stroma.
Stroma are light-yellow to red in color
and are 1-2 mm in diameter. Wind-blown
spores are released from the stroma and infect grains and grasses which
are flowering (pollinating). Once infected, a grain flower is replaced
by a sticky fungal mass called 'honey-dew' which contains millions of
new fungal spores. These new spores are spread to other healthy
kernels on the same grain head or to other heads by insects, wind or
As infected plants mature, the fungus develops into the hard
rain.
sclerotia once again.
'Extension Specialist, Crop Sci. Dept., Oregon State Univ.,
Corvallis, OR 07331
Ext/CrS 48
11/83
The fungus is favored by cool, wet weather for sclerotia germination,
dry conditions for initial spore spread, and cool weather, which prolongs the grain flowering period to allow honey-dew spread.
Why is the fungus harmful?
Yields are reduced by formation of the sclerotia.
Grain containing
0.3% ergot (by weight) is graded as ergoty and is generally not salable.
More importantly, ergot is poisonous and can cause serious
losses if feed to livestock and poultry. Animals fed large quantities
of ergot over an extended period of time develop a dry gangrene resulting in the loss of hooves, ears, tails, combs and wattles.
Spontaneous
abortion and loss of milk can occur in cows or sows fed even small
amounts of ergot.
The best recommendation is to not feed ergoty grain;
however, if you must, watch animals closely for symptoms or unusual
behavior, and consider the following:
1)
2)
3)
Brood sows, bred and milking cows are most susceptible and
should not be fed ergoty grain.
Cattle are more susceptible to ergotism than other livestock.
The USDA Poisonous Plant Research Laboratory in Logan, Utah,
suggests that cattle not be allowed to consume more than 1
ounce of sclerotia per head per day.
In general, for all animals, keep the percentage of sclerotia
as low as possible. Run the grain through a cleaner to
remove large sclerotia and/or mix ergoty grain with clean
Historigrain to reduce the amount present to 0.1% or less.
cally, ergoty grain was immersed in a 20% salt solution (40
lbs salt in 25 gals water) which caused the sclerotia to
float and allowed the ergot to be skimmed off. The grain was
then washed to remove the salt and dried. This procedure is
still effective for small lots of grain.
How is ergot controlled?
1)
Prevent its introduction into your field by using ergot-free
seed grain.
2)
If some ergot is present in seed grain, plant at a depth of
Deep planting does not allow the sclerotia
1-1 to 2 inches.
to develop spore producing bodies. Alternatively, store the
grain for 2 years and then use as seed as sclerotia lose
their viability with time.
3)
If the field is already contaminated, bury the sclerotia by
plowing, destroy weedy grasses in and around the field, and
if possible rotate to a non-susceptible crop (alfalfa,
Burning of stubble, where posclovers, potatoes, etc.).
sible, is also an effective control measure.
4)
Pasture infected fields before seed heads begin to flower.
5)
When harvesting an infected field, keep grain from outside
rounds separate as it is likely to have the highest ergot
content due to proximity to weedy grasses.